Vibration can be a cause or a solution of problems in subterranean locations. It can be a quantity that has to be controlled so that equipment or drill strings do not fatigue. It can be a force that creates acoustic signals that can be sensed in a variety of situations to monitor well conditions as for example in U.S. Pat. No. 5,080,189. It can be used to advantage to advance screens into a gravel pack using an augur in combination with a vibrator as shown in U.S. Pat. No. 6,877,561. Vibrators can be configured to pass tools until needed to function as a vibrator as shown in U.S. Pat. No. 6,866,104.
Typically, a vibrator is used in a tool string being run in to avoid getting stuck or to try to get the string to release if it gets stuck for a variety of reasons such as hole collapse in open hole when advancing through unconsolidated formations. One such vibrator whose basics will be discussed in detail below is U.S. Pat. No. 6,474,421. Other relevant art includes U.S. Pat. Nos. 7,575,051; 6,675,909 and 7,264,055.
FIGS. 1a-1c are a simplified half section presentation of the vibrating tool in U.S. Pat. No. 6,474,421 that provides flow induced axial vibration. The string 10 supports the housing 12. There is a flowpath 14 with a movable dart valve 16 in the flow path 14. The dart valve 16 has a closed nose 18 and lateral outlets 20. A spring 22 bears on shoulder 24 in the housing 12 to push the dart valve 16 uphole and in an opposite direction as the flow from the surface represented by arrow 26. An impact sleeve 28 is biased uphole by spring 30 supported from surface 32 in housing 12. Flow from the surface, represented by arrow 26 moves the dart valve 16 toward the impact sleeve 28. Initially the nose 18 contacts the impact sleeve 28 to stop flow and to initiate tandem movement of the dart valve 16 and the impact sleeve 28. Both springs 22 and 30 are compressed as this happens. The dart valve 16 is abruptly stopped by shoulder 34 for a downhole oriented axial pounding blow and the dart valve 16 separates from the impact sleeve 28. This opens a gap between the dart valve 16 and the impact sleeve 28 so that flow can start again. With the onset of flow, the spring 30 drives up the impact sleeve 28 against the shoulder 36 for a jarring uphole blow in the axial direction.
While this design has worked well it is limited by the axial direction of the opposed vibration impacts as the tool cycles continuously as described above with the flow continuing. What is needed and provided by the present invention is a way to also provide lateral vibration in conjunction with the axial vibration while still keeping the device simple for continuing trouble free operation. Those skilled in the art will better appreciate the present invention that provides vibration in lateral directions as well as axial vibration for more effective release of stuck strings or to better prevent sticking in the first place by a review of the description of the preferred embodiment and the associated drawings while at the same time realizing that the full scope of the invention is to be determined by the appended claims.